I am trying to freeze water into an ice rink quickly. Can I add liquid oxygen to it?

Question

I am thinking that if I add 50-100 gallons of liquid oxygen to the 2000 gallons of cold (35F) water in my skating rink, the temperature should drop at least 5 degrees and I can be skating in a few hours. But I am not chemist. Any thoughts?

Answer 1

I would not do this for two reasons….
First, because your plan of freezing the water will not work with the amount of the liquid Oxygen you specified, and
Secondly because any water which does freeze could trap some of the boiling Oxygen inside, this would then build up pressure and may blow holes in your ice rink.

If you have 2000 gallons for water at 35° F (1.67° C), the water has a mass of about 7570 kg. In order to freeze this water into ice at 32° F, a lot of energy must be extracted.
Water has a specific heat of 4.184 kJ/kg °C and a Latent heat of fusion of 334 kJ/kg.
Q = mc(delta T)
Q = m*L
Where Q is the heat energy released, m is the mass of water, c is the specific heat, (delta T) is the change in temperature, and L is the latent heat of fusion. To find the net energy released, one must add the energies released of both cooling the water and freezing the water.
Q = m(c(delta T) + L)
Plugging into these values, we find the total Q needed to be given off by the water is: 2.58 E6 kJ.

If we assume that all of this energy will be absorbed by the boiling Oxygen (we neglect any absorbed by the vaporous Oxygen), then we can calculate just how much liquid Oxygen it will take.

Liquid Oxygen gas a density of 1.141 kg/L. Oxygen gas has a molar mass of 32.00 g/mol. The Latent heat of vaporization of Oxygen is 6.82 kJ/mol = 213 kJ/kg.
The energy absorbed by liquid Oxygen boiling into a vapor is given as,
Q = m*L
If we set Q to be the same value as the energy given off by the water we can calculate the mass of Liquid O2 needed,
2.58 E6 kJ = m * 213 kJ/kg
Mass of Oxygen needed = about 12100 kg,
And using the density of liquid Oxygen, this mass would have a volume of about 10600 Liters (2800 gallons)….far greater than the 100 gallons you suggested.
Check these figures yourself to ensure accuracy. There was a lot of converting involved from unit to unit, but the specific heats, latent heats, densities, … should all be readily available on the internet, as well as unit converted.
2000 gallons of water is a lot of water and water is a pretty energy intensive thing to freeze.


My second reason is not as quantitative…but it comes from my experience with dry ice (solid Carbon Dioxide which sublimes into a gas at room temperature).
If you place dry ice in water it will sublime much faster than if left out in the air, it will also produce a bunch of white “fog”. But if you put enough dry ice in the water, the water’s temperature will cool down enough so that the liquid water will begin to freeze into solid ice on the dry ice. When this layer of solid water ice forms around the dry ice, the subliming CO2 cannot escape and becomes trapped. Eventually the pressure will build and built beneath the water-ice later up until the point where the ice bursts to relieve the pressure. If you add liquid Oxygen to liquid water, portions of the water near the liquid O2 might freeze amount it and trap it. Even though water might be a solid at 32° F, Oxygen certainly is not…so although the water might be finished with its phase changes, the liquid Oxygen will continue to boil into a gas and pressure may build. Undesirable results may ensure if these pockets of Oxygen gas are allowed to form in your ice rink.

Answer 2

Liquid oxygen is pretty lethal stuff, and will make most materials combustible. I know that the water in your ice rink might not fall into this category, but using liquid nitrogen would be a whole lot safer! And how do propose to spread the stuff around?

Answer 3

Any time you add anything to another substance - ie making a solution - you will actually LOWER the temperature at which this substance freezes, making it take LONGER to freeze. This is called freezing point depression, and happens with any solution.

My advice - ask someone who owns a skating rink how they do it, and/or have patience.

Answer 4

sure even though it wasnt on objective. pipes iced up, broke, water poured out floor moist, iced up up because of the fact it became on 5 ranges outdoors and 31 interior... we controlled to skate to the automobile to flow to motel mutually as the priority have been given fixed ..... communicate a pair of massive fee..... oh properly now i'm in Florida so optimistically i will in basic terms would desire to rigidity approximately being blown away - lol